Channel loss compensation circuits

ABSTRACT

A receiver circuit includes a plurality of receivers, each of the receivers being associated with a carrier of a plurality of carriers, and a decoupler configured to receive a transmission signal from a transmission channel and output a plurality of divided transmission signals to the plurality of receivers. An equalizer is configured to modify either the transmission signal or one of the divided transmission signals.

PRIORITY CLAIM

The present application is a divisional of U.S. application Ser. No.15/377,283, filed Dec. 13, 2016, which is a continuation of U.S.application Ser. No. 14/954,003, filed Nov. 30, 2015, now U.S. Pat. No.9,543,993, issued Jan. 10, 2017, each of which is incorporated herein byreference in its entirety.

BACKGROUND

Radio frequency interconnects (RFIs) are sometimes included in anintegrated circuit for communicating data between components of theintegrated circuit. RFIs include transmitters that communicate data toreceivers via a plurality of transmission channels. To transmit thedata, the transmitters modulate the data to be transmitted using aplurality of carriers. The modulated data is transmitted to thereceivers. To receive the data, the receivers demodulate receivedsignals from the carriers. Each transmission channel has a frequencyresponse, which causes channel loss. For example, five carriers thateach have a different frequency have different channel losses. Channelloss degrades the quality of the transmitted data.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 2 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 3 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 4 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 5 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 6 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 7 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 8 is a block diagram of a radio frequency interconnect, inaccordance with one or more embodiments.

FIG. 9 is a block diagram of an equalizer, in accordance with one ormore embodiments.

FIG. 10 is a block diagram of an equalizer, in accordance with one ormore embodiments.

FIG. 11 is a block diagram of a delay element, in accordance with one ormore embodiments.

FIG. 12 is a block diagram of a gain compensation driver, in accordancewith one or more embodiments.

FIG. 13 is a block diagram of a gain compensation driver, in accordancewith one or more embodiments.

FIG. 14 is a flowchart of a method of transmitting and receiving data,in accordance with one or more embodiments

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

RFIs include transmitters that communicate data to receivers using aplurality of carriers. Each transmission channel by which data iscommunicated to the receivers has a frequency response, which causeschannel loss. Channel loss degrades the quality of the transmitted data,and introduces noise to the transmission. The noise introduced has anegative effect on a signal-to-noise ratio that affects the quality of atransmitted signal and the performance of an RFI and increases a risk oferrors in decoding the received data.

FIG. 1 is a block diagram of an RFI 100, in accordance with one or moreembodiments. RFI 100 comprises a plurality of transmitters 101 a-101 n(collectively referred to as transmitters 101) configured to transmitdata Data_1-Data_N (collectively referred to as transmission data) to aplurality of receivers 103 a-103 n (collectively referred to asreceiver(s) 103) by way of a transmission channel 105. RFI 100 includesa combiner 107 on a transmitter-side of the transmission channel 105 anda decoupler 109 on a receiver-side of the transmission channel 105. Thecombiner 107 is communicatively coupled with the transmitters 101 andthe transmission channel 105. The decoupler 109 is communicativelycoupled with the receivers 103 and the transmission channel 105. A gaincompensation driver 113 is communicatively coupled between the combiner107 and the transmission channel 105. The transmitters 101 arecommunicatively coupled with the transmission channel 105 by way of thegain compensation driver 113 and the combiner 107. An equalizer 115 iscommunicatively coupled between the decoupler 109 and the transmissionchannel 105. The receivers 103 are communicatively coupled with thetransmission channel 105 by way of the equalizer 115 and the decoupler109.

The transmitters 101 are each associated with a transmission carrier 117ta-117 tn and the receivers 103 are each associated with a receptioncarrier 117 ra-117 rn (transmission carriers and reception carriers arecollectively referred to as carriers 117). Carriers 117 are, forexample, carrier signals or carrier waves, generated by one or morecarrier generators (not shown). Transmission carriers 117 ta-117 tn havefrequencies that correspond to respective reception carriers 117 ra-117rn. The carriers 117 are modulated by the corresponding transmitters 101to communicate the transmission data to the receivers 103 as atransmission signal. Each transmitter 101 receives respectivetransmission data Data_1-Data_N and outputs a corresponding transmissionsignal Tx_1-Tx_N (collectively referred to as transmission signals Tx).The receivers 103 use the receiving carriers 117 to demodulate receivedtransmission signals Rx_1-Rx_N (collectively referred to as receivedtransmission signals Rx) to recover the transmission data. Thedemodulated transmission data is read by the receivers 103 or output bythe receivers 103 to a device capable of reading the demodulatedtransmission data.

The combiner 107 is configured to receive the transmission signals Txfrom the transmitters 101, to combine the transmissions signals Tx, andto output a combined transmission signal S1. Signal S1 is communicatedto the decoupler 109 by way of the transmission channel 105. Thetransmission channel 105 is a single channel transmission line ormedium. In some embodiments, transmission channel 105 is a dual-channeltransmission line or medium. In some embodiments, transmission channel105 is a multi-channel transmission line or medium. In some embodiments,a quantity of channels included in the multi-channel transmission lineor medium is less than a quantity of carriers 117.

The transmission channel 105 has a frequency response that causescarriers 117 to have different amounts of channel loss, which affectsthe amplitude of the received transmission signals Rx. Channel lossreduces a strength of transmission signals Tx and/or signal S1. Thechannel loss degrades signal-to-noise ratio performance, whichnegatively affects the quality and/or speed of the received transmissionsignals Rx corresponding to the transmission signals Tx and/or signalS1. If the quality of the received transmission signals Rx are degraded,then the transmission data recovered therefrom, is degraded. If thespeed with which the transmission signals Tx and/or signal S1propagating through transmission channel 105 is negatively affected, anamount of time taken to recover the transmission data from the receivedtransmission signal Rx is increased, which increases processing timesand introduces delay. RFI 100, accordingly, includes gain compensationdriver 113 and/or equalizer 115 to compensate for the channel loss andshape the frequency response.

Gain compensation driver 113 is a channel loss compensation circuitconfigured to receive signal S1 and to output a signal S2 to thetransmission channel 105. Signal S2 is a modified signal S1 tocompensate for the channel loss introduced by transmission channel 105.The gain compensation driver 113 is configured to generate signal S2 bydelaying signal S1 by a delay factor T_(gcdb), amplifying the delayedsignal by a gain factor α_(gcd1), and adding the amplified delayedsignal to signal S1. In some embodiments, the channel loss compensatedfor by the gain compensation driver 113 is an estimated channel loss,because signal S2 has not yet been transmitted through the transmissionchannel 105 before signal S1 is received by the gain compensation driver113. In some embodiments, the channel loss compensated for by the gaincompensation driver 113 is based on measured results from passingsignals through the transmission channel 105. In some embodiments, gainfactor α_(gcd1) is capable of being modified to change the amount thedelayed signal is amplified to compensate for different amounts ofchannel loss.

Signal S2 output by gain compensation driver 113 is transmitted throughtransmission channel 105 to receivers 103. En route to receivers 103,transmission channel 105 causes channel loss to signal S2 propagatingthrough the transmission channel 105. Signal S3 is output fromtransmission channel 105. Signal S3 corresponds to signal S2 followingthe channel loss in the transmission channel 105. In some embodiments,gain factor α_(gcd1) is set at a selected value such that signal S3 isequal to signal S1 or within a predefined signal-to-noise ratiothreshold of signal S1 after the channel loss is introduced to signal S2by transmission channel 105.

Equalizer 115 is a channel loss compensation circuit configured toreceive signal S3 and to output a signal S4 to the decoupler 109. SignalS3 is modified by equalizer 115 to compensate for the channel lossintroduced by transmission channel 105 and/or excess gain introduced tosignal S2 remaining after transmission of signal S2 through transmissionchannel 105. The equalizer 115 is configured to generate signal S4 bydelaying signal S3 by a delay factor T_(eqb), amplifying the delayedsignal by a gain factor α_(eq1), and adding the amplified delayed signalto signal S3. In some embodiments, gain factor α_(eq1) is capable ofbeing modified to change the amount the delayed signal is amplified.Changing gain factor α_(eq1) affects an amount of channel loss theequalizer 115 is configured to compensate. In some embodiments, gainfactor α_(eq1) is set at a selected value such that signal S4 is equalto signal S1 or within a predefined signal-to-noise ratio threshold ofsignal S1 after the gain compensation driver 113 compensates for thechannel loss introduced by transmission channel 105 and/or channel lossis introduced to signal S2 by transmission channel 105.

In some embodiments, RFI 100 is free from a gain compensation driver113. If gain compensation driver 113 is absent from RFI 100, signal S3received by equalizer 115 is signal S1 (i.e., the combined transmissionsignals Tx without gain compensation) after signal S1 is transmittedthrough transmission channel 105.

In some embodiments, RFI 100 is free from including an equalizer 115. Ifequalizer 115 is absent from RFI 100, signal S3 output by transmissionchannel 105 is communicated directly to decoupler 109.

Decoupler 109 is configured to receive signal S4. In some embodiments,if the equalizer 115 is absent from RFI 100, then decoupler 109 isconfigured to receive signal S3. Decoupler 109 is configured to divide areceived signal (i.e., signal S4 or signal S3) into receivedtransmission signals Rx, and to communicate the received transmissionsignals Rx to the respective receivers 103. For example, transmissiondata Data_1 transmitted by transmitter 101 a as transmission signal Tx_1is communicated to receiver 103 a and received by receiver 103 a asreceived transmission signal Rx_1, transmission data Data_2 transmittedby transmitter 101 b as transmission signal Tx_2 is communicated toreceiver 103 b and received by receiver 103 b as received transmissionsignal Rx_2, and transmission data Data_N transmitted by transmitter 101n as transmission signal Tx_N is communicated to receiver 103 n andreceived by receiver 103 n as received transmission signal Rx_N.

In some embodiments, RFI 100 is included in an integrated circuit. Insome embodiments, RFI 100 is an on-chip interconnect. In someembodiments, RFI 100 is over or at least partially within a substrate.In some embodiments, the components of RFI 100 are divided among two ormore integrated circuits or separate substrates. In some embodiments,transmission channel 105 is one or more of a wired or a wirelesscommunication channel.

FIG. 2 is a block diagram of an RFI 200, in accordance with one or moreembodiments. RFI 200 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by100. RFI 200 differs from RFI 100 in that RFI 200 includes a pluralityof gain compensation drivers 213 a-213 n (collectively referred to asgain compensation drivers 213) and a plurality of equalizers 215 a-215 n(collectively referred to as equalizers 215). The gain compensationdrivers 213 are each individually communicatively coupled withrespective transmitters 201 and with the combiner 207 on thetransmitter-side of the combiner 207. The equalizers 215 are eachindividually communicatively coupled with respective receivers 203 andwith the decoupler 209 on the receiver-side of the decoupler 209. Insome embodiments, combiner 207 and decoupler 209 are each directlycoupled with transmission channel 205. In some embodiments, at least oneintervening device is located between the combiner 207 and thetransmission channel 205 or between the decoupler 209 and thetransmission channel 205. Gain compensation drivers 213 are coupled withthe transmission channel 205 by way of the combiner 207. Equalizers 215are coupled with the transmission channel 205 by way of decoupler 209.

In RFI 200, each gain compensation driver 213 a-213 n receivesrespective transmission signal Tx_1-Tx_N from the transmitters 101. Thegain compensation drivers 213 are optionally configured to receivecarriers 217. The gain compensation drivers 213 are configured to modifythe transmission signals Tx to compensate for channel loss and outputsignals S1 a-S1 n to combiner 207. In some embodiments, gaincompensation drivers 213 use the carriers 217 to modify transmissionsignals Tx to generate signals S1 a-S1 n.

Gain compensation drivers 213 are configured to generate signals S1 a-S1n by delaying signals S1 a-S1 n by respective delay factorsT_(gcdb1)-T_(gcdbn), amplifying the delayed signals by respective gainfactors α_(gcd1)-α_(gcdn), and adding the amplified delayed signals tothe respective transmission signals Tx. In some embodiments, the channelloss compensated for by the gain compensation drivers 213 is anestimated channel loss, because signal S2 has not yet been transmittedthrough the transmission channel 205 before transmission signals Tx arereceived by the gain compensation drivers 213. In some embodiments, gainfactors α_(gcd1)-α_(gcdn) are capable of being modified to change theamount the delayed signal is amplified. Changing one or more of gainfactors α_(gcd1)-α_(gcdn) affects an amount of channel loss for whichthe gain compensation drivers 213 are configured to compensate. In someembodiments, delay factors T_(gcdb1)-T_(gcdbn) are equal. In someembodiments, delay factors T_(gcdb1)-T_(gcdbn) are not equal. In someembodiments, delay factors T_(gcdb1)-T_(gcdbn) are based on the carriers217. In some embodiments, gain factors α_(gcd1)-α_(gcdn) are equal. Insome embodiments, gain factors α_(gcd1)-α_(gcdn)n are not equal. In someembodiments, gain factors α_(gcd1)-α_(gcdn) are based on the carriers217.

Combiner 207 is configured to combine signals S1 a-S1 n and to outputsignal S2. Signal S2 output by combiner 207 is transmitted throughtransmission channel 205 to receivers 203. En route to receivers 203,transmission channel 205 introduces channel loss to signal S2. Signal S3is output from transmission channel 205. Signal S3 corresponds to signalS2 after the channel loss is introduced to signal S2 by transmissionchannel 205.

Decoupler 209 is configured to receive signal S3 and to divide signal S3into signals S4 a-S4 n (collectively referred to as signals S4). SignalsS4 are communicated to respective equalizers 215 for conversion toreceived transmission signals Rx that are communicated to the respectivereceivers 203.

Equalizers 215 are configured receive signals S4 and to output receivedtransmissions signals Rx_1-Rx_N to receivers 203. Signals S4 aremodified by equalizers 215 to compensate for the channel loss introducedby transmission channel 205 and/or excess gain introduced to signals S1remaining after transmission of signal S2 through transmission channel205. Equalizers 215 are configured to generate received transmissionsignals Rx_1-Rx_N by delaying signals Rx_1-Rx_N by respective delayfactors T_(eqb1)-T_(eqbn), amplifying the delayed signals by arespective gain factor α_(eq1)-α_(eqn), and adding the amplified delayedsignals to the respective signals S4. In some embodiments, gain factorsα_(eq1)-α_(eqn) are capable of being modified to change the amount thedelayed signal is amplified. Changing one or more of gain factorsα_(eq1)-α_(eqn) affects an amount of channel loss for which theequalizers 215 are configured to compensate. In some embodiments, delayfactors T_(eqb1)-T_(eqbn) are equal. In some embodiments, delay factorsT_(eqb1)-T_(eqbn) are not equal. In some embodiments, delay factorsT_(eqb1)-T_(eqbn) are based on the carriers 217. In some embodiments,gain factors α_(eq1)-α_(eqn) are equal. In some embodiments, gainfactors α_(eq1)-α_(eqn) are not equal. In some embodiments, gain factorsα_(eq1)-α_(eqn) are based on the carriers 217. In some embodiments, gainfactors α_(eq1)-α_(eqn) are set at selected values such that receivedtransmissions signals Rx_1-Rx-N are equal to transmission signalsTx_1-Tx_N, or within a predefined signal-to-noise ratio threshold oftransmission signals Tx_1-Tx_N after the channel loss is introduced tosignal S2 by transmission channel 205.

FIG. 3 is a block diagram of an RFI 300, in accordance with one or moreembodiments. RFI 300 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by200. RFI 300 differs from RFI 100 in that RFI 300 is free from includinggain compensation driver 113 (FIG. 1). Signal S1 is transmitted throughtransmission channel 305. Transmission channel 305 introduces channelloss to signal S1 and outputs signal S3.

FIG. 4 is a block diagram of an RFI 400, in accordance with one or moreembodiments. RFI 400 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by300. RFI 400 differs from RFI 100 in that RFI 400 includes a pluralityof gain compensation drivers 413 a-413 n and one equalizer 415. As such,in RFI 400, the transmitter-side of transmission channel 405 isconfigured similar to the transmitter-side of RFI 200 (FIG. 2), and thereceiver-side of the transmission channel 405 is configured like thereceiver-side of RFI 100 (FIG. 1).

FIG. 5 is a block diagram of an RFI 500, in accordance with one or moreembodiments. RFI 500 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by400. RFI 500 differs from RFI 100 in that RFI 500 is free from includinggain compensation driver 113 (FIG. 1). RFI 500 includes a plurality ofequalizers 515 a-515 n. Signal S1 is transmitted through transmissionchannel 505. Transmission channel 505 introduces channel loss to signalS1 and outputs signal S3. As such, in RFI 500, the transmitter-side oftransmission channel 505 is configured similar to the transmitter-sideof RFI 300 (FIG. 3), and the receiver-side of the transmission channel505 is configured similar to the receiver-side of RFI 200 (FIG. 2).

FIG. 6 is a block diagram of an RFI 600, in accordance with one or moreembodiments. RFI 600 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by500. RFI 600 differs from RFI 100 in that RFI 600 is free from includingequalizer 115 (FIG. 1). Signal S2 is transmitted through transmissionchannel 605. Coupler 609 receives signal S3 and is configured to dividesignal S3 into received transmission signals Rx.

FIG. 7 is a block diagram of an RFI 700, in accordance with one or moreembodiments. RFI 700 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by600. RFI 700 differs from RFI 100 in that RFI 700 includes a pluralityof gain compensation drivers 713 a-713 n. RFI 700 is free from includingequalizer 115 (FIG. 1). As such, in RFI 700, the transmitter-side oftransmission channel 705 is configured similar to the transmitter-sideof RFI 200 (FIG. 2), and the receiver-side of the transmission channel705 is configured similar to the receiver-side of RFI 600 (FIG. 6).

FIG. 8 is a block diagram of an RFI 800, in accordance with one or moreembodiments. RFI 800 comprises many of the features discussed withrespect to RFI 100 (FIG. 1), with the reference numerals increased by700. RFI 800 differs from RFI 100 in that RFI 800 includes one gaincompensation driver 813 and a plurality of equalizers 815 a-815 n. Assuch, in RFI 800, the transmitter-side of transmission channel 805 isconfigured similar to the transmitter-side of RFI 100, and thereceiver-side of the transmission channel 805 is configured similar tothe receiver-side of RFI 200 (FIG. 2).

FIG. 9 is a block diagram of an equalizer 915, in accordance with one ormore embodiments. Equalizer 915 is usable in place of any of theequalizers discussed herein. For example, in some embodiments, equalizer915 is an example embodiment of equalizer 115 (FIG. 1). One of ordinaryskill would recognize that the equalizers discussed herein are notlimited to the configuration discussed with respect to equalizer 915.

Equalizer 915 comprises a signal input 919, an adder 921 coupled withthe signal input, a signal output 923 coupled with the adder 921, adelay element 925 coupled with the signal output 923, and an amplifier927 coupled with the delay element 925 and with the adder 921. Signalinput 919 is configured to receive an input signal X(t). Input signalX(t) is representative of a signal received by an equalizer such assignal S3 (FIG. 1) or one of signals S4 a-S4 n (FIG. 2), for example.Signal output 923 is configured to output an output signal Y(t). Outputsignal Y(t) is representative of signal S4 (FIG. 1) or one of receivedtransmission signals Rx_1-Rx_N (FIG. 2), in some embodiments. Delayelement 925 is configured to receive the output signal Y(t), and delaythe output signal Y(t) by delay factor T_(eqb) to generate a delayedoutput signal. Amplifier 927 is configured to receive the delayed outputsignal, to amplify the delayed output signal by gain factor α_(eqd1),and to generate an amplified output signal. In some embodiments,amplifier 927 is a programmable gain amplifier having a selectable gainfactor α_(eqd1). Adder 921 is configured to receive the input signalX(t), to receive the amplified output signal from amplifier 927, and tocombine the input signal X(t) with the amplified output signal togenerate output signal Y(t).

In some embodiments, delay element 925 is a delay locked loop thatcauses the output signal Y(t) to be delayed by delay factor T_(eqb). Insome embodiments, delay element 925 is a logic circuit configured tocause the output signal Y(t) to be delayed by delay factor T_(eqb). Insome embodiments, delay element 925 is a clock frequency doublerconfigured to cause the output signal Y(t) to be delayed by delay factorT_(eqb). In some embodiments, delay factor T_(eqb) delays output signalY(t) by about half of the clock cycle of the output signal Y(t) toenable equalizer 915 to compensate for channel loss. As such, outputsignal Y(t) is about 180 degrees out of phase with input signal X(t). Insome embodiments, delay factor T_(eqb) delays the output signal Y(t) bya different amount to enable equalizer 915 to compensate for channelloss.

FIG. 10 is a block diagram of an equalizer 1015, in accordance with oneor more embodiments. Equalizer 1015 is usable in place of any of theequalizers discussed herein. For example, in some embodiments, equalizer1015 is an example embodiment of equalizer 115 (FIG. 1). One of ordinaryskill would recognize that the equalizers discussed herein are notlimited the configuration discussed with respect to equalizer 1015.

Equalizer 1015 includes features similar to those discussed with respectto equalizer 915 (FIG. 9), with the reference numerals increased by 100.Equalizer 1015 differs from equalizer 915 in that equalizer 1015 is amulti-tap equalizer that comprises a plurality of delay elements 1025a-1025 n (collectively referred to as delay elements 1025) coupled inseries and a plurality of amplifiers 1027 a-1027 n (collectivelyreferred to as amplifiers 1027) coupled between each delay element 1025and the adder 1021. A first delay element 1025 a is configured toreceive the output signal Y(t) and to generate a first delayed outputsignal. Each subsequent delay element 1025 is configured to receive thefirst delayed output signal or a subsequent delayed output signal from aprevious delay element 1025, and to generate a corresponding delayedoutput signal. The amplifiers 1027 are configured to amplify the firstdelayed output signal or corresponding subsequent output signals byrespective gain factors α₁-α_(N) to generate corresponding amplifiedoutput signals. Adder 1021 is configured to receive the input signalX(t), to receive the amplified output signals from amplifiers 1027, andto combine the input signal X(t) with the amplified output signals togenerate the output signal Y(t).

In some embodiments, the amplifiers 1027 are programmable gainamplifiers with selectable gain factors α₁-α_(N). In some embodiments,gain factors α₁-α_(N) are equal to one another. In some embodiments, atleast one of the gain factors α₁-α_(N) is different from at least one ofthe other gain factors α₁-α_(N).

FIG. 11 is a block diagram of a delay element 1125, in accordance withone or more embodiments. Delay element 1125 is usable in place of any ofthe delay elements discussed herein. For example, in some embodiments,delay element 1125 is an example embodiment of delay element 925 (FIG.9). One of ordinary skill would recognize that the delay elementsdiscussed herein are not limited to the configuration discussed withrespect to delay element 1125.

Delay element 1125 comprises a signal input 1127, a phase detector 1129coupled with the signal input 1127, a capacitor 1131 coupled with thephase detector 1129 and a voltage node 1133 configured to carry areference voltage, a voltage controlled delay line 1135 coupled with thesignal input 1127 and the phase detector 1129, and a signal output 1137coupled with the voltage delay line 1135 and with the phase detector1129.

Signal input 1127 is configured to receive an input signal A(t). Inputsignal A(t) is representative of signal S4 (FIG. 1) or one of receivedtransmission signals Rx_1-Rx_N (FIG. 2) output by the equalizersdiscussed herein. Output signal B(t) is representative of a delayedoutput signal generated by delay elements 925 or 1025, for example. Thephase detector 1129 is configured to receive the output signal B(t) andthe input signal A(t) and to compare the output signal B(t) with theinput signal A(t). The phase detector 1129 is configured to determine aphase difference between the output signal B(t) and the input signalA(t). Based on the determined phase difference, the phase detector isconfigured to output a voltage control signal Vctrl. Based on thevoltage control signal Vctrl, the voltage controlled delay line 1135 isconfigured to modify an amount the output signal B(t) is delayedcompared to the input signal A(t). For example, if the delay factorT_(eqb) is selected to delay the input signal A(t) by one half of theclock cycle of the input signal B(t), the phase detector 1129 outputsvoltage control signal Vctrl to cause the voltage controlled delay line1135 to delay the input signal A(t) by an amount that results in theoutput signal B(t) being 180 degrees out of phase with the input signalA(t).

FIG. 12 is a block diagram of a gain compensation driver 1213, inaccordance with one or more embodiments. Gain compensation driver 1213is usable in place of any of the gain compensation drivers discussedherein. For example, in some embodiments, gain compensation driver 1213is an example embodiment of gain compensation driver 113 (FIG. 1). Oneof ordinary skill would recognize that the gain compensation driversdiscussed herein are not limited to the configuration discussed withrespect to gain compensation driver 1213.

Gain compensation driver 1213 comprises a signal input 1219, an adder1221 coupled with the signal input 1219, a signal output 1223 coupledwith the adder 1221, a delay element 1225 coupled with the signal output1223, and an amplifier 1227 coupled with the delay element 1225 and withthe adder 1221. Signal input 1219 is configured to receive an inputsignal M(t). Input signal M(t) is representative of a signal received bya gain compensation driver such as signal S1 (FIG. 1) or one oftransmission Tx_1-Tx_N (FIG. 2), for example. Signal output 1223 isconfigured to output an output signal Y(t). Output signal N(t) isrepresentative of signal S2 (FIG. 1) or one of signals S1-Sn (FIG. 2).Delay element 1225 is configured to receive the input signal M(t), anddelay the input signal M(t) by delay factor T_(gcdb) to generate adelayed output signal. Amplifier 1227 is configured to receive thedelayed input signal, to amplify the delayed output signal by gainfactor α_(gcd1), and to generate an amplified input signal. In someembodiments, amplifier 1227 is a programmable gain amplifier having aselectable gain factor α_(gcd1). Adder 1221 is configured to receive theinput signal M(t), to receive the amplified input signal from amplifier1227, and to combine the input signal M(t) with the amplified inputsignal to generate output signal N(t).

In some embodiments, delay element 1225 is a delay locked loop thatcauses the output signal N(t) to be delayed by delay factor T_(gcdb). Insome embodiments, delay element 1225 is logic circuit configured tocause the output signal N(t) to be delayed by delay factor T_(gcdb). Insome embodiments, delay element 1225 is a clock frequency doublerconfigured to cause the output signal N(t) to be delayed by delay factorT_(gcdb). In some embodiments, delay factor T_(gcdb) delays outputsignal N(t) by about half of the clock cycle of the output signal N(t)to enable gain compensation driver 1213 to compensate for channel loss.In some embodiments, delay factor T_(gcdb) delays the output signal N(t)by a different amount to enable gain compensation driver 1213 tocompensate for channel loss. In some embodiments, delay element 1225comprises a phase detector and a voltage controlled delay line similarto delay element 1125 (FIG. 11).

FIG. 13 is a block diagram of a gain compensation driver 1313, inaccordance with one or more embodiments. Gain compensation driver 1313is usable in place of any of the gain compensation drivers discussedherein. For example, in some embodiments, gain compensation driver 1313is an example embodiment of gain compensation driver 113 (FIG. 1). Oneof ordinary skill would recognize that the gain compensation driversdiscussed herein are not limited to the configuration discussed withrespect to gain compensation driver 1313.

Gain compensation driver 1313 includes features similar to thosediscussed with respect to gain compensation driver 1213 (FIG. 12), withthe reference numerals increased by 100. Gain compensation driver 1313differs from gain compensation driver 1213 in that gain compensationdriver 1313 is a multi-tap gain compensation driver that comprises aplurality of delay elements 1325 a-1325 n (collectively referred to asdelay elements 1325) coupled in series and a plurality of amplifiers1327 a-1327 n (collectively referred to as amplifiers 1327) coupledbetween each delay element 1325 and the adder 1321. A first delayelement 1325 a is configured to receive the input signal M(t) and togenerate a first delayed output signal. Each subsequent delay element1325 is configured to receive the first delayed output signal or asubsequent delayed output signal from a previous delay element 1325, andto generate a corresponding delayed output signal. The amplifiers 1327are configured to amplify the input signal M(t), the first delayedoutput signal, or corresponding subsequent output signals by respectivegain factors 1−Σ|α_(K)|, α₁-α_(N-1) to generate corresponding amplifiedinput signals. Adder 1321 is configured to receive the amplified inputsignals from amplifiers 1327, and to combine the amplified input signalsto generate the output signal N(t).

In some embodiments, the amplifiers 1327 are programmable gainamplifiers with selectable gain factors 1−Σ|α_(K)|, α₁-α_(N-1) that arecapable of being changed to modify the overall amount of gain added toor subtracted from input signal M(t). In some embodiments, gain factors1−Σ|α_(K)|, α₁-α_(N-1) are equal to one another. In some embodiments, atleast one of the gain factors 1−Σ|α_(K)|, α₁-α_(N-1) is different fromat least one of the other gain factors 1−Σ|α_(K)|, α₁-α_(N-1). In someembodiments, α₁-α_(N-1), are less than zero. In some embodiments,α₁−α_(N-1) are greater than zero.

FIG. 14 is a flowchart of a method 1400 of transmitting and receivingdata, in accordance with one or more embodiments. In some embodiments,method 1400 is implemented by a RFI such as one of RFI 100 through RFI800 discussed with respect to FIGS. 1-8.

In operation 1401, a plurality of transmitters each receive data to becommunicated to a plurality of receivers by way of a transmissionchannel. In step 1403, the transmitters of the plurality of transmittersmodulate the received data using carriers associated with thetransmitters to generate transmission signals.

Based on the configuration of the RFI used to implement method 1400,method 1400 proceeds to one of operation 1405, operation 1407, oroperation 1409.

In operation 1405, the transmission signals are modified by respectivegain compensation drivers to compensate for channel loss introduced bythe transmission channel, the modified signals are combined by acombiner into a combined signal, and the combined signal is transmittedthrough the transmission channel.

In operation 1407, the transmission signals are combined into a combinedsignal by a combiner, the combined signal is modified by a gaincompensation driver, and the modified combined signal is transmittedthrough the transmission channel.

In operation 1409, the transmission signals are combined into a combinedsignal by a combiner, and the combined signal is transmitted through thetransmission channel.

Based on the configuration of the RFI used to implement method 1400,method 1400 proceeds to one of operation 1411, operation 1413, oroperation 1415.

Because the RFIs used to implement method 1400 include at least one gaincompensation driver or at least one equalizer, method 1400 only proceedsto operation 1415 by way of operation 1405 or operation 1407.

In operation 1411, the combined signal transmitted through thetransmission channel is received by an equalizer, modified by theequalizer to compensate for channel loss, and the combined signalmodified by the equalizer is divided into a plurality of receivedtransmission signals.

In operation 1413, the combined signal transmitted through thetransmission channel is received by a decoupler, divided into aplurality of signals, the plurality of signals are individually receivedby equalizers of a plurality of equalizers, the equalizers of theplurality of equalizers modify the divided signals to compensate forchannel loss and output a plurality of received transmission signals.

In operation 1415, the combined signal transmitted through thetransmission channel is received by a decoupler and divided into aplurality of received transmission signals.

In operation 1417, the received transmission signals are demodulated byrespective receivers of the plurality of receivers that correspond tothe transmitters of the plurality of transmitters using carriers thatcorrespond to the carriers used to modulate the data to be transmitted.Demodulating the received transmission signals results in data that isreadable by the receivers or another device coupled with the receivers.

In some embodiments, a receiver circuit includes a plurality ofreceivers, each receiver of the plurality of receivers being associatedwith a carrier of a plurality of carriers, a decoupler configured toreceive a transmission signal from a transmission channel and output aplurality of divided transmission signals to the plurality of receivers,and an equalizer configured to modify one of the transmission signal ora divided transmission signal of the plurality of divided transmissionsignals.

In some embodiments, a receiver circuit includes a decoupler configuredto receive a transmission signal from a transmission channel, divide thetransmission signal into a plurality of divided transmission signals,each divided transmission signal of the plurality of dividedtransmission signals corresponding to a carrier frequency, and outputthe plurality of divided transmission signals. A receiver is configuredto receive a divided transmission signal of the plurality of dividedtransmission signals, and an equalizer is configured to cause thedivided transmission signal of the plurality of divided transmissionsignals received by the receiver to be modified.

In some embodiments, a receiver circuit includes a decoupler configuredto receive a transmission signal from a transmission channel, divide thetransmission signal into a plurality of divided transmission signals,each divided transmission signal of the plurality of dividedtransmission signals corresponding to a carrier frequency, and outputthe plurality of divided transmission signals to a correspondingplurality of receivers. An equalizer is configured to cause theplurality of divided transmission signals received by the plurality ofreceivers to be modified.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A receiver circuit, comprising: a plurality ofreceivers, each receiver of the plurality of receivers being associatedwith a carrier of a plurality of carriers; a decoupler configured toreceive a transmission signal from a transmission channel and output aplurality of divided transmission signals to the plurality of receivers;and an equalizer configured to modify one of the transmission signal ora divided transmission signal of the plurality of divided transmissionsignals, wherein the equalizer modification is based on afrequency-dependent loss of the transmission signal introduced by thetransmission channel.
 2. The receiver circuit of claim 1, wherein theequalizer is one equalizer of a plurality of equalizers, and eachequalizer of the plurality of equalizers is configured to modify acorresponding divided transmission signal of the plurality of dividedtransmission signals.
 3. The receiver circuit of claim 2, wherein eachequalizer of the plurality of equalizers is configured to receive acorresponding carrier of the plurality of carriers, and modify thecorresponding divided transmission signal of the plurality of dividedtransmission signals by applying a gain factor based on thecorresponding carrier of the plurality of carriers.
 4. The receivercircuit of claim 2, wherein each equalizer of the plurality ofequalizers is configured to receive a corresponding carrier of theplurality of carriers, and modify the corresponding divided transmissionsignal of the plurality of divided transmission signals by applying adelay based on the corresponding carrier of the plurality of carriers.5. The receiver circuit of claim 1, wherein the equalizer is configuredto apply a gain factor to the one of the transmission signal or thedivided transmission signal of the plurality of divided transmissionsignals based on an estimated value of the frequency-dependent loss ofthe transmission channel.
 6. The receiver circuit of claim 1, whereinthe equalizer is configured to modify the one of the transmission signalor the divided transmission signal of the plurality of dividedtransmission signals based on a predefined signal-to-noise ratiothreshold of the one of the transmission signal or the dividedtransmission signal of the plurality of divided transmission signals. 7.The receiver circuit of claim 1, wherein the equalizer is configured tomodify the transmission signal by being coupled between the transmissionchannel and the decoupler.
 8. A receiver circuit, comprising: adecoupler configured to receive a transmission signal from atransmission channel, divide the transmission signal into a plurality ofdivided transmission signals, each divided transmission signal of theplurality of divided transmission signals corresponding to a carrierfrequency, and output the plurality of divided transmission signals; areceiver configured to receive a divided transmission signal of theplurality of divided transmission signals; and an equalizer configuredto cause the divided transmission signal of the plurality of dividedtransmission signals received by the receiver to be modified, whereinthe equalizer modification is based on a frequency-dependent loss of thetransmission signal introduced by the transmission channel.
 9. Thereceiver circuit of claim 8, wherein the equalizer is configured tomodify one of the transmission signal or the divided transmission signalof the plurality of divided transmission signals by compensating for afrequency-dependent loss of the transmission signal introduced by thetransmission channel.
 10. The receiver circuit of claim 8, wherein theequalizer is configured to receive one of the transmission signal or thedivided transmission signal of the plurality of divided transmissionsignals as an input signal, delay the input signal by a delay factor,amplify the delayed input signal by a gain factor, add the amplifieddelayed signal to the input signal to generate an output signal, andprovide the output signal as a corresponding one of a modifiedtransmission signal or a modified divided transmission signal of theplurality of divided transmission signals.
 11. The receiver circuit ofclaim 8, wherein the equalizer comprises: a signal input configured toreceive an input signal; a signal output configured to output an outputsignal; an adder coupled between the signal input and the signal output;and a delay element and an amplifier coupled in series between thesignal output and the adder.
 12. The receiver circuit of claim 11,wherein the delay element is one delay element of a plurality of delayelements coupled between the signal output and the adder, and theamplifier is one amplifier of a plurality of amplifiers coupled betweenthe signal output and the adder.
 13. The receiver circuit of claim 12,wherein each amplifier of the plurality of amplifiers has a gain factor,and at least one gain factor of an amplifier of the plurality ofamplifiers is different from one other gain factor of another amplifierof the plurality of amplifiers.
 14. The receiver circuit of claim 11,wherein the amplifier has a programmable gain factor.
 15. The receivercircuit of claim 11, wherein the delay element is configured to delaythe output signal by a delay factor configured to cause the outputsignal to be about 180 degrees out of phase with the input signal.
 16. Areceiver circuit, comprising: a decoupler configured to receive atransmission signal from a transmission channel, divide the transmissionsignal into a plurality of divided transmission signals, each dividedtransmission signal of the plurality of divided transmission signalscorresponding to a carrier frequency, and output the plurality ofdivided transmission signals to a corresponding plurality of receivers;and an equalizer configured to cause the plurality of dividedtransmission signals received by the plurality of receivers to bemodified, wherein the equalizer modification is based on afrequency-dependent loss of the transmission signal introduced by thetransmission channel.
 17. The receiver circuit of claim 16, wherein theequalizer is one equalizer of a plurality of equalizers, each equalizerof the plurality of equalizers is coupled between the decoupler and acorresponding receiver of the plurality of receivers.
 18. The receivercircuit of claim 17, wherein each equalizer of the plurality ofequalizers is configured to receive a corresponding divided transmissionsignal of the plurality of divided transmission signals as an inputsignal, delay the input signal by a delay factor, amplify the delayedinput signal by a gain factor, add the amplified delayed signal to theinput signal to generate an output signal, and provide the output signalas a corresponding modified divided transmission signal of the pluralityof divided transmission signals.
 19. The receiver circuit of claim 18,wherein each equalizer of the plurality of equalizers is furtherconfigured to receive a carrier signal having the carrier frequency ofthe corresponding divided transmission signal of the plurality ofdivided transmission signals, and at least one of delay the input signalby the delay factor or amplify the delayed input signal by the gainfactor based on the carrier frequency.
 20. The receiver circuit of claim18, wherein at least one of the delay factor or gain factor has a valuecorresponding to an estimated value of the frequency-dependent losscompensation level based on the carrier frequency.